title: Quantitative analysis of NK1 receptor in the human brain using PET with 18F-FE-SPA-RQ.
abstract: 18F-fluoroethyl-SPA-RQ (18F-FE-SPA-RQ) was recently developed as a radioligand for the measurement of neurokinin 1 (NK1) receptor with PET. In this study, we used 18F-FE-SPA-RQ with PET to visualize and quantify NK1 receptor in the human brain.
  
  
  METHODS
  PET scans were performed on 7 healthy men after intravenous injection of 18F-FE-SPA-RQ. Binding potential (BPND) was calculated by the indirect kinetic, simplified reference tissue model (SRTM), and ratio methods. The indirect kinetic method was used as the gold standard method and was compared with the SRTM method, with scan times of 180, 270, and 330 min, and with the ratio method, with time integration intervals of 120-180, 210-270, and 300-330 min. The cerebellum was used as the reference brain region.
  
  
  RESULTS
  Regional radioactivity was highest in the caudate head and putamen; mid level in the parahippocampus, cerebral cortex, and thalamus; and lowest in the cerebellum. BPND values by the indirect kinetic method were 3.15 +/- 0.36, 3.11 +/- 0.66, 1.17 +/- 0.25, and 0.46 +/- 0.14 in the caudate, putamen, parahippocampal region, and thalamus, respectively. For cerebral cortical regions, BPND values by the indirect kinetic method were 0.94 +/- 0.23, 0.82 +/- 0.15, 0.76 +/- 0.15, and 0.69 +/- 0.16 in the occipital, temporal, frontal, and anterior cingulate cortices, respectively. BPND values by the SRTM and ratio methods were in good agreement with those by the indirect kinetic method (r = 0.94-0.98).
  
  
  CONCLUSIONS
  The regional distribution of 18F-FE-SPA-RQ was in agreement with previous PET studies and postmortem studies of NK1 receptor in the human brain. The ratio method will be useful for clinical research of psychiatric disorders, for the estimation of NK1 receptor without arterial blood sampling and long dynamic PET.
authors.affiliation: Molecular Neuroimaging Group, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan.
authors.forename: Masaki
authors.initials: M
authors.lastname: Okumura
authors.forename: Ryosuke
authors.initials: R
authors.lastname: Arakawa
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ito
authors.forename: Chie
authors.initials: C
authors.lastname: Seki
authors.forename: Hidehiko
authors.initials: H
authors.lastname: Takahashi
authors.forename: Harumasa
authors.initials: H
authors.lastname: Takano
authors.forename: Eisuke
authors.initials: E
authors.lastname: Haneda
authors.forename: Ryuji
authors.initials: R
authors.lastname: Nakao
authors.forename: Hidenori
authors.initials: H
authors.lastname: Suzuki
authors.forename: Kazutoshi
authors.initials: K
authors.lastname: Suzuki
authors.forename: Yoshiro
authors.initials: Y
authors.lastname: Okubo
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Suhara
mesh_terms: D000328:Adult; D001158:Arteries / Q000378:metabolism; D001921:Brain / Q000000981:diagnostic imaging* / Q000378:metabolism*; D006801:Humans; D008297:Male; D010880:Piperidines / Q000097:blood / Q000378:metabolism; D049268:Positron-Emission Tomography; D018040:Receptors, Neurokinin-1 / Q000032:analysis* / Q000378:metabolism; D015203:Reproducibility of Results; D013777:Tetrazoles / Q000097:blood / Q000378:metabolism; D013997:Time Factors; D055815:Young Adult
chemical_list: C517420:(2-fluoromethoxy-5-(5-trifluoromethyltetrazol-1-yl)benzyl)(2-phenylpiperidin-3-yl)amine; D010880:Piperidines; D018040:Receptors, Neurokinin-1; D013777:Tetrazoles